Bloat causes the stomach to swell up (or "bloat"). The
reasons for the swelling remain elusive and will be the subject of
additional studies. The dog cannot expel the gas and the stomach
continues to swell until it twists (often as much as 360 degrees). This
condition is called acute gastric dilatation volvulus (GDV syndrome) or
torsion. Torsion is a life-threatening situation. If the stomach twists,
its cavity becomes sealed off, closing off its upper and lower openings
through which gas may normally escape. The swollen, distended stomach
puts pressure upon the spleen, liver, pancreas, heart, and lungs,
compressing nerves and blood supplies, quickly resulting in shock and
death. Immediate surgery is the only treatment for this condition.

Strangulationis
a form of bloat affecting the intestines. A loop of the intestine
becomes constricted (strangulated) by slipping through an abnormal
opening. This can happen when the dog has adhesions in its abdominal
cavity, as often develop after abdominal surgery.

Intussusception
occurs when a section of the intestine telescopes into itself. This
condition is more common in puppies than adults and occurs most often
after a long siege of diarrhea. It is a life-threatening condition
requiring immediate veterinary attention.

In a simple attack of
bloat, in which the stomach fills with gas, the veterinarian will insert
a tube down the throat, relieve the gas, pump out the stomach and give
the stomach a thorough washing. Acute GDV or torsion, strangulation, and
intussusception all require immediate veterinary care and surgery.
Post-operative treatment for shock requires prolonged hospitalization.
In the case of torsion, the stomach should be surgically "tacked down"
to the body wall to prevent the twist from occurring again, because once
a dog suffers from bloat, it will most likely happen again, often within
days of the first attack. For strangulation and intussusception, surgery
is needed to repair the intestines, and the dog also requires prolonged
hospitalization for treatment of shock.

The
tragedy of this disorder is how frequently it occurs when the owner is
not home, but returns to find their Leonberger has died from GDV. It is
a disease that strikes suddenly without warning, and is fatal unless
immediate veterinary care is provided.
Symptoms to watch for include
extreme restlessness, excessive salivation, drooling, and an attempt to
vomit or defecate. As the condition progresses, the stomach area appears swollen and the dog shows
signs of pain when the abdomen is pressed. Rapid breathing, pale-colored
mouth membranes and collapse are signs of shock due to a more advanced
phase of bloat. If untreated, a dog will die within a short time. An
alert owner who recognizes the early signs of a simple attack of bloat
and gets immediate medical attention for his Leonberger may prevent the
more severe form of acute GDV or torsion. Sometimes a dog will progress
from bloat to torsion in minutes, so do not attempt to medicate your
Leonberger, get it to a veterinarian immediately. Because time is so
important in saving a bloated animal from death, it is a good idea to
know where your local Emergency Pet Clinic is located (if your own
veterinarian does not cover emergencies), and the quickest routes there.
Do a dry run before the emergency exists and you will save precious
moments if an emergency does develop.

Dr. Larry Glickman at the School of Veterinary
Medicine at Purdue University completed the most comprehensive study of
this disorder in 1998. The Akita, a breed that I have worked for in many
areas for more than 25 years, participated in this study. The Akita was
selected because it is in the top ten of breeds prone to suffer GDV.
Dr. Glickman’s study provided the following conclusions:

• The incidence of GDV has increased by 1,500% over the past 30 years.

• Thirty percent of all GDV cases are fatal. In contrast,
dogs properly treated have an 80% probability of surviving a
bloat episode.

• The recurrence rate of GDV in dogs conservatively treated for bloat
i.e., without surgery, approaches 100%. The recurrence rate following
gastropexy is less than 5%. Always insist on immediate surgery for your
Leonberger, do not bring your dog home without corrective surgery.

• Personality is a major predictor of GDV, the happy,
easy-going dog has a lower risk of GDV. He suggests using behavior
modification with anxious, fearful dogs.

• The incidence of GDV increases with advancing age. The increased
risk begins at three years of age.

• Do not breed dogs if a first-degree relative has
bloated and do not breed dogs that have bloated. Having a grandparent,
parent or sibling with GDV increases the risk of bloat.

• Males and females bloat almost equally.

• Spaying and neutering have no effect
on the incidence of GDV.

• Dogs characterized by their owners as chronically
underweight are at higher risk than dogs characterized as average weight
or even overweight.

• The faster a dog eats, the greater the risk of bloat. This
increased risk may be related to gulping air while eating. Reduce the
eating speed of your Leonberger.

• Seventy percent of bloat cases occur late at night or
early in the morning. Dr. Glickman is investigating a swallowing
disorder as a possible contributing factor.

• There is a relationship between dogs with intestinal gas and dogs
that bloat. Dogs that belch often have a 60% increased risk of bloat.
Dogs with frequent bouts of flatulence have a 20% increased risk.

• Elevating the food bowl increases the risk of GDV.

• Dogs fed only dry food are at increased risk, while dogs fed a mix
of dry food with table scraps are at decreased risk.

• Feeding dry food containing rendered meat with bone among the first
four ingredients decreased a dog’s risk of bloat by 53%.

• Feeding multiple small meals reduces the risk of
bloat.

• Having water available at all times reduces the risk.

• In high-risk breeds (like Akitas), consider having a prophylactic
gastropexy done when the dog is spayed or neutered. The recovery is not
very different than for sterilization alone, and the cost of the
procedure is considerably less than an emergency surgery. (Approximately
$3,000 compared to an additional $200.)

Is a raw food diet
a factor in prevention of this disease? We will have to wait until Dr.
Glickman completes his dietary-management study. The “Natural Akita”
email list, which is comprised of advocates for the raw food diet, claim
one case of bloat in an Akita since its inception in 1997--that could be
coincidence.

Is
Bloat A Neurological Disease?

My
experience with bloat ended successfully for my Akita, Tootsie--she
expanded like a balloon five hours after eating, was rushed to the
emergency hospital two blocks from home and underwent successful
gastropexy. Her surgeon was amazed at the complete lack of motility; he
mentioned that in all GDV surgeries he had performed on various breeds,
gastrointestinal motility was lacking in each dog. I assisted the
veterinarian in washing undigested food from Tootsie’s stomach, food
that she had eaten three days earlier.

His statement led
me to research “motility,”
the propulsion of food along the length of the digestive tract. What
activated the smooth muscle contractions and why would this action
cease, leaving undigested food in the stomach? Time out for a simple
anatomy lesson!

The dog's nervous system is comprised of the central and
peripheral/autonomic nervous systems. The central nervous system
consists of the brain and the neural tube running the length of the
spinal cord. The brain is the body's central computer, analyzing and
processing all information both internally and externally. Based on
external stimuli, the brain decides a course of action, and relays the
information through the central nervous system to the body or to a
specific organ. Sensory nerves carry information to the brain and spinal
cord; motor nerves carry signals back to the body, to spur movement of
the muscles, or to stimulate glands into activity.

Dr.
Zen of the Gastrointestinal Research Laboratory, Gunma University,
Maebashi, Japanhas
been studying motilin, which is an important factor in controlling the
pattern of smooth muscle contractions in the upper gastrointestinal
tract. Motilin is
considered a hormone—a “housekeeping hormone,” which is secreted into
the circulation at intervals of every one hundred minutes, to sweep out
undigested material from the stomach and small intestine. Motilin also
stimulates secretions of bile and pancreatic enzymes into the duodenum.

Very little is
known about the control of motilin. Apparently, it is stimulated by
cholinergic neurons in the enteric nervous system, which is a part of
the autonomic nervous system.
The enteric nervous system controls
all of the digestive processes from the secretion of motilin, to the
propulsion of food through the gastrointestinal tract. Enzyme secretions
from the pancreas and bile from the gallbladder are controlled by
motilin. The enteric nervous system contains sensory neurons,
inter-neurons, and motor neurons. Its circuitry can autonomously sense
the tension, and the chemical environment in the gut and regulate blood
vessel tone, motility, secretions, and fluid transport. The system is itself governed by the central
nervous system.

Organophosphate insecticides
like Dursban, Malathion,
and Diazinon,and carbamate insecticides (Carbaryl
and Propoxur), as well as the latest family of nicotinoids (nicotine
derivatives), are
all neurotoxins.
These chemicals
work by interrupting the electrochemical processes that nerves use to
communicate with muscles and with other nerves. A key chemical in
communication between neurons is called a neurotransmitter—acetylcholine
is the neurotransmitter involved in muscle contractions. Acetylcholine
(produced by the body) is used to "fire" the neuron, and then is
inhibited by an enzyme called cholinesterase. In a healthy nervous
system, acetylcholine passes a signal (fires) between one neuron and
another, or between a nerve and a muscle receptor. The enzyme
cholinesterase is released and binds to the acetylcholine, allowing the
nerves to rest. Cholinesterase, however, is not unique to insects--it is
also a component of the canine nervous system. (The enteric nervous
system uses the major neurotransmitters, like acetylcholine, serotonin,
Motilin.)

The nicotinoid insecticides like imidacloprid,
activate the nicotinic acetylcholine receptor, but do so steadily, since
they are insensitive to the action of cholinesterase. This persistent
activation leads to an over stimulation of cholinergic synapses, and
results in hyper-excitation, convulsions, paralysis, and the death of
the insect. The
organophosphate group of insecticides inactivates cholinesterase to prevent the degradation of
the neurotransmitter acetylcholine; this results in a constant flow of
acetylcholine at the synapse. The carbamate
insecticides mimic acetylcholine--as the acetylcholine builds up, the
muscles of the body become over-stimulated, leading to paralysis and
death.

Neurotoxic pesticides
are highly toxic to mammals with a chemical characteristic that leads
them to dissipate very slowly once introduced to the body. They are used
directly on dogs, as well as in their environment. The assumption is
that small amounts are sufficient to kill an insect but will not harm a
dog, but is it possible to really limit exposure? These chemicals are
now ubiquitous in our environment. For example, the Environmental
Protection Agency estimates that 60 million pounds of organophosphate
pesticides are applied within the United States every year. Chlorpyrifosis the most widely used insecticide in the Chesapeake Bay
district. Recent studies show that this organophosphate chemical is
consistently present in the air, rain and surface waters of the
Chesapeake Bay region, suggesting a long environmental half-life.

Perhaps more frightening than knowing these chemicals exist in our
environment, is knowing they exist and bioaccumulateinside the
bodies of our children and our dogs.

• A study to measure the
organophosphorus
pesticide exposure among children living in
two Seattle metropolitan area communities
revealed that 99% of the
children had
measurable levels of organophosphate
pesticide metabolites.

• In
Minnesota, the 1997 Children's Pesticide
Exposure Study looked at urine samples from
102 children; 93% had pesticide levels higher
than in recent population-based studies of
adults in the United States.

Dr. Itoh’s studies
involve dogs but his goal is to treat humans with “altered motility
gastrointestinal disorders.” Dr. Itoh (together with Dr. S.
Omura),
discovered that by using a synthetic motilin, he could effectively
stimulate the release of motilin in the dog, initiate the contractions,
and begin the next phase of digestion (which causes gastric emptying).
Eventually, Itoh found that the antibiotic, erythromycin simulated the
action of motilin. He was able to isolate the component in erythromycin
responsible for the action, which he called EM574, now patented as”
by Takeda Chemical Industries’ pharmaceutical
division.

Many questions
remain for future research projects. As with most diseases, prevention
when possible may guarantee survival for your Leonberger. Follow the
recommendations of Dr. Larry Glickman, and avoid the use of neurotoxic
chemicals. These chemicals persist in the residential environment for
longer than a year, and they bioaccumulate, meaning the chemicals are
taken up and stored in fatty tissue faster than they are broken down
(metabolized) or excreted. Most important, because of individual genetic
susceptibilities based not only on major histocompatibility complex
differences but also on differences in toxin metabolism, lifestyles, and
exposure
rates, individuals will react
differently to the same chemicals.

The three breeds known to comprise the Leonberger: Great
Pyrenees,
Saint Bernard and Newfoundland are all in the top ten of breeds that are
prone to bloat with some frequency. Therefore, you must become
aware of the symptoms, understand the dangers and plan ahead--just in
case!